It is not always advisable for a patient to be extremely sedated during some procedures, since the sedation may cause sudden involuntary movements. On the other hand, it is never advisable for the patient to be too awake and uncomfortable. One example of this scenario is associated with eye surgeries (such as cataract removal, retina surgery, or the like), which requires the patient to be somewhat sedated, yet remain aware of his/her surroundings. These surgeries require the use of microscopic-based instruments to perform the procedure where any slight movement by the patient (such as trying to indicate pain or another issue) is problematic.
In these cases, the patient is the only one who knows exactly how he/she feels. Thus, if the patient's pain level is being exceeded, he/she should be able to request more sedation or pain control without needing to speak to make this request known. In most situations, however, the patient is unable to talk (for some oral surgery procedures), or should not talk and cause undesirable movement. In situations where the patient's face is covered during a procedure, it is difficult to ascertain the patient's pain level.
Additionally, there are situations where a patient is given general anesthesia for a procedure where a local anesthesia may suffice. For example, if there is a language barrier between the patient and the staff, the staff may opt for the use of a general anesthesia (especially in situations where an interpreter is not permitted in the operating room). Similar problems arise where verbal communication is equally problematic—with a stroke patient, a deaf-mute patient, and the like.